Gas-heated clothes drier



GAS HEATED CLOTHES DRIER Filed Oct. 18. 1947 s Shets-Sheet 2 6 Q C CD Q3 Y 2 42 as J 4 4 FIG? INVENTORS GEORGE E. M/NTNER BY ARTHUR R.CONSTZIVT/NE AT TOR/V5 Y Feb. 21, 1950 e. E. MINTNER ETAL 2,498,172

GAS HEATED CLOTHES DRIER File d Oct. 18, 1947 8 Sheets-Sheet 3 Fla 4 Q34IN V EN TORS GEORGE E. MIN T/VER BY ARTHUR R. CONSENT/NE ATTORNEY Feb.21, 1950 a. E. MINTNER ETAL 2,498,172 GAS HEATED CLOTHES DRIER FiledOct. 18, 1947 8 Sheets-Sheet 4 6 V IN V EN T 0R5 GEORGE E. MIN TNERARTHUR R. CONSTANT/NE ATTORNEY Feb. 21, 1950 s. E. MIN-musk ETAL2,498,172 GAS HEATED CLOTHES DRI'ER I Filed Oct. 18, 1947 8 Sheets-Sheet5 FIG. 6

ATTORNEY Feb. 21, 1950 e. E.- MINTNER ETAL 2,498,172

GAS HEATED CLOTHES DRIER Filed Oct. 18, 1947- a Sheets-Sheet e o a QFIG. 7 78 I N V EN TORS GEORGE E. MIN TNE I? ARTHUR R. CONSENT/11EATTORAE Y Feb. 21, 1950 G. E. MINTNER ET AL 2,498,172

GAS HEATED CLOTHES DRIER Filed Oct. 18. 1947 s Sheets-Sheet 8 FIG. /2

IN V EN TORS GEORQE E M/NTNER BY ARTHUR R. CONSENT/NE A T TORNE YPatented Feb. 21, 1950 YVUZNITED STATES PATENT OFFICE GAS-HEATED CLOTHESDRIER George E. Mintner and Arthur R. Constantine, South Bend, Ind.,assignors to Bendix Home Appliances, Inc, South Bend, Ind., acorporation of Delaware Application October 18, 1947, Serial No. 780,808

gas flame and in which the products of combustion are allowed tocirculate in the dryer but with a minimum possibility of contact withthe clothes to be dried while also assuring a maximum use of the heat inthe gas for drying purposes.

It is a further object to so locate and control the air intake to thedryer so that air necessarily required to replace air discharged withmoisture may be used to reduce th temperature of the products ofcombustion of the heating gas and to thereby assure satisfactory maximumtemperature for the parts of the machine adjacent the clothes to bedried and to prevent the outer walls and other parts of the machine frombecoming overheated. 1

Another object is to provide an arrangement of the parts of a gas dryerso that the products of combustion leaving the burner are first carriedthrough a conduit for indirect heat transfer to air used in drying andsubsequently the products of combustion are caused to flow around andinto the rotatable clothes containing member.

Still a further object of the invention is to provide means of balancingthe pressure in several parts of the dryer through which heated gasesmust flow so that desired gas flow and heat fiow is obtained which willassure a maximum use of the heat generated by the combustion of the gas.

The above and other objects of the invention will appear more fully fromthe following more detailed description and by reference to theaccompanying drawings forming a part hereof and wherein Figure 1 is afront view of the dryer with the front cover removed showing majorportions of the mechanism.

Figure 2 is a side view partly in section showing the cylindrical drumand parts of the gas circulation system, particularly the means ofdirecting the products of combustion above the gas flame.

Figure 3 is a sectional view from the front of the machine showingparticularly the duct for recirculating the air into and out of theclothes containing cylinder. 7

Figure 4 is a top view of the duct substantially on the line 4-4 ofFigure 3.

Figure 5 is a view partly in section showine: the several gas controlvalves;

Figure 6 is a wiring diagram showing the elec trical connections to theseveral units.

Figure '7 is a sectional view from the front of the machine similar toFigure 3 showing a proposed modifioation of the air recirculating ductand the arrangement for the conduit directing the products of combustionabove the burner.

' Figure 8 is also a showing of the modified form, and is a section fromthe front of the machine,"but with the front plate and the recirculatingduct removed to show the entrance to the heating chamber and the radiantshield therein.

Figurel9 is a side view and shows the vertical portions of the duct andthe housing for the conduit in the modified form shown in Figures 7 and8.

Figure 10 is a view similar to Figure 9, but with the wall which housesthe conduit removed.

Figure 11 is a top view of the vertical section of the conduit from line|lll of Figure 9.

Figure 12 shows the front plate and the openings therein as used in themodified form.

Referring to the drawings, a cylinder III which serves as a dryingchamber is mounted for rotation, it being supported centrally on itsrear wall I l by a bearing l2 and further supported through a forwardlyextending annular flange l3 which forms a central opening in the frontof the machine and which is supported bytwo rollers II and 15. Theannular flange I3 is also designed to provide an opening for access intothe cylinder ill for inserting the wet clothes and removing the dryclothes after drying. The front of the cabinet is closed by a door IIAas shown in Figure 2. Suitable insulation I8 may be provided between thecylindrical member I! and the outer cabinet panels It as shown. Theclothes cylinder I0 is provided with a perforated or screened front wallit and when the cylinder III is supported for rotation this perforatedfront wall l3 rotates parallel to and closely adjacent a front plate ordividing wall 20. This dividing wall 20 carries a duct 2! and an inlet22 formed by an opening in the wall 20 opens into said duct 2| adjacenta blower wheel 23 which is located in the duct 2i. The blower wheel 23therefore assists entry of air into the duct 2| through the opening 22through the perforated wall l8 of the cylinder It. The air thus causedto circulate into the duct 2| through the opening 22 passes horizontallyacross the top of the machine through the duct 2| and downwardly throughthe vertical portion 2|A of the duct 2| toa second opening 24 throughthe wall 23 which opens adjacent the perforated wall I! of the cylinderl and serves as an outlet for the duct 2|. Thus the rotation of theblower wheel 23 will cause air to be circulated and'recirculated outfrom the cylinder I0, into duct 2|, through the opening 22, and willreturn the air into the cylinder ll through the duct outlet opening 24.

For the purpose of supplying heat, a gas burner 23 is mounted below thevertical portion 2| A- of the duct 2|. and this burner 25 is surroundedby a stove housing 23. The stove housing 24 is provided with a topmember 21 which serves as a wall between the stove housing 23 and thebottom oi the vertical portion 2 IA of the duct. The

top member 2'! is provided with a pine connection 23 which provides acommunication with a conduit 29 for carrying the products of combustion.This conduit 29 which extends upwardly through the vertical portion 2|Aof the duct 2| makes a right angle bend, and as shown in Fi ure 2, opensinto a mixing chamber 30. The mixing chamber 30 is constructed adjacentthe cylindrical wall H which surrounds the rotatable clothes cylinderIll. The mixing chamber 30 has a plurality of holes 3| which providecommunication from the mixing chamber 3. into the space between thecylindrical wall l1 and the periphery of the clothes cylinder ll.

The mixing chamber 30 is provided with an inlet opening 32 at the backof the dryer which opening has a shield 33 attached thereto. The opening32 is on the opposite end of the mixing chamber 30 from the outlet ofthe stack or conduit 29. When the gas burner 25 is in operation theproducts of combustion from the gas circulate upward through the stackor conduit 23 into the mixing chamber 30. Inasmuch as the stack orconduit 23 is inside the re-circulating duct 2| there will be a transferof heat to the circulating air by the passage of such air over the outersurface of the conduit 29. However, the transfer takes out only aportion of the heat carried in the products of combustion and theseproducts of combustion which enter the mixing chamber 30 are of arelatively high temperature; in fact of such high temperature that itwould not be practical to force them directly into the openings 3| andonto the clothes contained in the cylinder it without some provision toreduce the temperature thereof. This reduction in temperature isaccomplished by providing that the inlet air necessary to replace theair which is ejected from the machine is taken in through the opening32. In other words, the possibilities for intake of air into otherportions of the machine is restricted, thus forcing the air to come in,to a major degree, through the opening 32, and this air will dilute theproducts of combustion in the mixing chamber 30 to such a' degree that asatisfactory temperature will be realized. It is evident that a certainamount of outside air will necessarily be taken into the machine andthis construction assures that it will be taken in at a point which willreduce the temperature of the products of combustion to a practicaltemperature for admission into the container defined by the outer drumII. It also is evident that the openings 3| are so positioned that themixture of the products of combustion and inlet air first contact theouter periphery of the rotating cylinder l0 although the circulation issuch that the major amount of air circulates around the front of thecylinder through the open screened front wall l9 thereof.

An outlet 34 to the outside of the machine is so positioned that only aportion of the recirculated air passing through the duct 2| will flowout from the duct 2| through the outlet 34 and such outlet 34 is betweenthe blower outlet and the vertical heat transfer portion 2|A of duct 2|as is shown in Figure l the outlet 34 is positioned at the right handend of the horizontal portion of duct 2| on the outlet side of theblower housing formed around the blower wheel 23. The outlet 34 is alsorelatively close to the blower wheel 23 and there is a positive flow ofair near the outlet 34 so that such outlet, as determined by the size ofthe duct 2| and the opening 34, is a positive outlet induced by pressureset up by thebower wheel 23. Inasmuch as the blower wheel 23 produces anincrease in pressure in the duct 2| and tends to reduce pressure in thecylinder It on the other side of the opening 22 it is evident that theair displacement brought about by releasing air out from the outlet 34will induce a pressure somewhat less than atmospheric in the drum I0 andinasmuch as such reduction in pressure exists it will tend to draw airfrom the mixing chamber 30 through the openings 3| into the drum orcylinder Therefore there will be a pressure condition induced bydisplacement of air'out from the outlet 34 such that an inlet of airinto the mixing chamber 30 will occur in from the conduit 29 carryingproducts of combustion over the burner 25 and also will induce an inletof air from the opening 32 at the-back of the machine thereby mixing theproducts of combustion with outside air in the amount necessary toreplace the air forced out through the outlet 34. It is understood'thatthe air ejected from the outlet 34 is necessary to discharge moistureladen air from the dryer. The outlet 34 is positioned between the outletof the blower and the heat transfer portion of duct 2| to insure apositive outward flow and to avoid unnecessary waste of heat.

The gas for combustion is fed to the machine through a pipe 38 connectedto a valve 40 which valve has a gas connection to a pilot 4| andathermocouple assembly comprising a thermocouple lead 42 and athermocouple 42A. The thermocouple lead 42 forms a current conductorcomprising two metal tubes, a copper outer tube which surrounds aninsulated inner one. The innerand outer elements of each are brazedtogether to form so called cold junctions and the inner and outer tubeare welded together at the tip to form the hot junction 42A. As shown inFigures 1, 3, and 5 this hot junction 42A is so located adjacent thepilot burner 4| that the hot junction 42A will actually be in the flamefrom the pilot burner 4| when the latter is lighted. Suflicientelectricity is generated by the temperature differential between the hotand cold junctions to energize the electromagnet 40A thereby holding thevalve 40 open as shown in Figure 5. The valve 4|! is initially opened bymanually depressing .a plunger 43, which permits a flow of gas to thepilot 4| and enables it to be lighted manually. After lighting the pilot4|, the plunger 43 must be held down until the hot junction 42A of thethermocouple is heated sufliciently to generate electricity to cause theelectromagnet 40A to hold the valve 40 open, after which the plunger maybe released and the valve 40 will remain open. A valve 44 controlled by4 pilot 4 the gas will then flow through these two val es into asolenoid operated valve 45. This valve is opened and normally held openby the actuation of a solenoid 46. The electrical circuit for actuatingthis solenoid will be described more completely hereinafter. After thegas has been allowed to flow through the valve 45 by actuation of thesolenoid 46 it may enter a safety valve 41 which is a spring operatedvalve having a normal tendency to close but which is held open by theaction of the spring 49A which maintains a constant upward pull on thelever 48. The spring 49A is connected through a cable 49 to a fusibleelement 50 of suitable material having a melting point whichis selectedto conform to a temperature slightly above the maximum temperaturenormally attained in operation. This element 56 is mounted as shown inFigure 1 on the wall of the duct 2| and as long as the temperature onthe wall of the conduit is below the melting point above mentioned, thevalve 41 will remain open. However, should some control component failand cause the temperature on the wall of duct 2| to exceed themeltingpoint of the fusible element 50, the valve will close by spring action.

The gas, after having passed through the valve by an electric motor 58.A shaft 51 carries the.

cam 51A actuating individual switches 66 and 6| and this cam 51A istherefore rotated by timer I motor 58. The individual switch 66 controlsthe circuits for the main drive motor 62 and timer motor 58 whileindividual switch 6| controls the circuit to gas valve 45 in series withthe thermostat contacts 53A. The units above mentioned including themotor 62 and the timer 56 are shown on Figure 1 as well as on Figure 6.The belt connections for rotating clothes cylinder III are shown inFigure 1. The motor 62 drives the cylinder Io through belts 63 and 64,annular flange l3, and pulleys 65 and 66, while the blower 23 is driventhrough the belt 61 also shown in Figure 1.

41, enters the mixing chamber 38 which is connected to the previouslymentioned gas burner 25. Thus it is apparent that the heating system forthe dryer herein described is provided with two positive safety devicesin addition to those employed in normal operation, the actuation ofeither of which will result in the flow of gas to the burner 25 beingout off completely. The thermocouple assembly -42-42A acts to shut offthe gas through closing the valve 40 if the pilot is extinguished,whereas-the spring 49A and cable 46 attached to the fusible element 58will act to cut 011 the flow of gas at thevalve 41 if the temperature inthe dryer exceeds a predetermined maximum.

Considering Figure 6 which is an electrical wiring diagram showing thecircuit which controls the operation of the dryer it is noted that thesolenoid operated gas valve 45 previously mentioned in the abovedescription is shown in Figures 5 and 6 as controlled by the solenoidunit 46. This solenoid unit 46, when actuated through the electricalcircuit 5l-52 causes gas to be fed into the burner 25 (see Figures 1 and5). The electrical conductor 5| connects with a thermostat 53 which isshown diagrammatically in Figure 6 and is also shown on the drawingFigure 1. This thermostat has a temperature responsive element 54, shownin Figure l, positioned in the air circulating duct 2|. This thermostatmay be of the general type disclosed in U. S. Patent 2,197,229. Thisthermostat 53 has its contacts 53A in series with the electricalconductor 5|, and will close or fail to close that circuit at contacts53A depending upon the temperature in duct 2| at which the circuit willbe closed or broken by change in volume of liquid carried in thethermostat as shown in Figure 6. As shown in Figure 1 the temperature atwhich this thermo- As shown on the electrical circuit drawing Figure 6,the volt power circuit furnishes electrical current through thethermostat 52 to the lines 5| and 52 provided the cam operated severalcams carried by the shaft 51 on the timer 56 and the rate of rotation ofthe shaft 51 are so arranged that desired time for operation of themotor 62 for the rotation of the cylinder I 0 is provided andv duringsuch time the circuit through switch 6| is closed to furnish current tothe solenoid 46 and thereby hold the gas valve 45 in an open positioninorder to furnish gas to the burner 25.

, In operation the gas pilot 4| is first manually lighted while holdingdown the plunger 43. When the pilot 4| has continued burning asulficient length of time to assure that the hot junction 42A hasgenerated sufficient electricity to enable the electromagnet 46A to holdthe valve 46 in an open position to feed gas to the pilot,

the handle 44A is turned to open the main valve 44. The timer 56 may beset in motion by rotating it to a starting position so that the timermotor 58 and the main motor 62 will be put in rotation. Such positionwill provide electrical current controlled by the switch unit 60 forboth motors 58 and 62 and will also at the same time provide electricalcurrent through switch 6| and, if the thermostat 53 is set for arelatively high temperature, will allow current to be fed to thesolenoid 46 of the gas valve 45. This will cause the gas valve 45 to beopened which will feed gas to the burner 25. The gas burned in the stove26 will heat the top member 21 and adjacent parts of the stove and theproducts of combustion and heated gas will flow up through theconnection 28 and the conduit 29 which will also be heated and transferheat to the recirculating air in duct 2|. The products of combustionthen enter the mixing chamber 30 adjacent the holes 3| which communicatewith the housing surrounding the rotatable cylinder I. As previouslymentioned, the air pressure in the mixing chamber 30 is such that thetendency will be to permit flow of the heated products of combustion outthrough the holes 3| and into the space surrounding the rotatablecylinder I0. Inasmuch as the gases which are so carried through thehousing 3|, di-

76 luted by inlet air from opening 32 as previously 7 mentioned. will berequired to contact the outside surface of the cylinder ID the heat inthese gases will be used to heat the cylinder although the gases willeventually flow into the cylinder |9 itself.

The products of combustion in their passage through the conduit 29, willheat the conduit 29 and the air passing in duct 2| around the conduit.Therefore as the gas is burned in the stove housing 25 and passes intothe conduit 29, a portion of the heat of the gas is used in heating thestove housing and the conduit 29 and furthermore the products ofcombustion circulate between member I1 and cylinder l9 so that there isa heat transfer and use of the burned gases to heat the portion of thedryer cylinder directly adjacent the clothes to be dried and also thereis a partial transfer of heat to the clothes in the air recirculatingduct 2| in the front of the machine by flow of air around conduit 29. Itcan therefore be stated that heat is removed from the gas to theclothesby indirect transfer through heated surfaces and also heated by laterdirect passage of products of combustion into the clothes cylinder.However, the use of an indirect transfer of a portion of the heatassures that the final direct contact temperature of the gas products ofcombustion on the material to be dried will be materially lower thanwould be the case if products of combustion were allowed to contact theclothes without initial indirect heat transfer as herein disclosed.

Figures 7 to 12 inclusive show a modification wherein the conduit 29 isenclosed to prevent the air and lint circulating through the duct 2|from coming in direct contact with the walls of the conduit 29, and withflow of air over conduit 29 into cylinder |9 from the outside. In somecases this construction is desirable particularly for drying specialtypes of fabrics which give off lint particles having a tendency tocling to surfaces of relatively high temperature.

As shown in Figure 11, the conduit 29 is sealed off from the air duct 2|by a. housing composed of three walls, 15, I6, 11 and a plate 19. Thewalls 15 and TI, as shown in Figures 9 and 10, extend from a pointslightly above the bend 19 in the conduit 29 to a point adjacent butspaced above the top member 21 of the stove housing 26. The space 16Aprovides for inlet of air from the outside around the conduit 29 andinto the clothes cylinder l9 through screen 92 and screened front walll9 of cylinder ID.

The wall I is cut off diagonally at a point somewhat above the stovehousing 21, and to this diagonal lower edge of the wall" is secured abottom member 99, which member serves as the bottom of a vertical duct8| which is connected to the horizontal duct 2| As shown in Figure 12the wall 18 is provided with a long vertical screened opening 82 whichis adjacent the conduit 29, enabling heated air passing around conduit,29 to pass into the clothes containing cylinder |9 through the screenedfront wall l9. The vertical opening 82 is widened at the bottom toprovide an opening 92 from the vertical duct 8| into the cylinder l9through the screened front wall |9 thereof. Thus it appears that thereare two closely adjacent openings into the cylinder I9, one fromrecirculating duct BI and the other'from the chamber in which conduit 29is enclosed. Since the air taken around conduit 29 comes from outsidethere is no possibility of lint content in such air and since the flowblends immediately with the recirculated air from conduit 8| thetemperaturewlll not be too high. As can be seen from inspection ofFigure 10 the bottom member 89 is slanted diagonally downward toward theopening 93 to facilitate passage of the air into the cylinder It. At thejunction of the horizontal duct 2| and the vertical duct 8| there issituated an air scoop 84 which deflectsair from the horizontal duct 2|into the outlet 94 .which was described in the first form of theinvention for removing vapor laden air from the machine.

In order to prevent the outside wall of the machine from becomingoverheated due to heat radiation from the conduit 29, an openingindicated as 85 in Figure 11 is provided to permit the passage of coolair between the wall 11 of the conduit housing and the outside wall. Theair which passes through this opening 85 is enabled to enter the mixingchamber 39 through an opening 96 in the wall 18 as shown in Figures 7and 12. The mixing chamber 39 is substantially the same as themixingchamber in the first described form, with the exception that inthe modification herein described,a radiant shield 81 is provided toprevent the outside walls of the machine from becoming overheated.

In operation the modified form is not greatl different from the firstdescribed form. Air is withdrawn from the rotatable cylinder l9 throughthe opening 22 in the wall 19 by means of the fan or blower 23 and iscirculated through the horizontal duct 2|. Upon reaching the junction ofthe horizontal duct 2| and the vertical duct 8|, a small portion of theair is picked up by the air scoop 94 and is discharged from the machinethrough the outlet 34. However, the major portion of the air passingthrough the duct 2| is deflected into the vertical duct 8|. Uponstriking the bottom member 9| which slants toward the opening 83 in thewall 18, the air is caused to pass through the opening 83 and throughthe screened front wall IQ of the rotatable cylinder l9.

It will be noted that at no time does the air circulating through theducts 2| or 8! come in direct contact with the walls of the conduit 29.However, a partial heat transfer is afforded into the duct 9| throughthe wall 15 and directly into the rotatable cylinder l9 through thescreened opening 82 in the wall l9 adjacent the screened front wall I9.But the products of combustion and the greater portion of the heatgenerated by the gas burner 25 are carried through the conduit 29 intothe mixing chamber 39 where they are free to pass through the holes 3|and through the perforated front wall of the rotatable cylinder |9. Aspreviously mentioned, the radiant shield 81 prevents the overheating ofthe outside walls and insures that the'heat in the mixing chamber 39will be transmitted to the clothes inside the rotatable cylinder.

Although this invention has been disclosed by reference to a particularmachine which has been found practical in actual operation, it is notintended to limit the scope of this invention to that disclosure orotherwise than by the terms of the appended claims.

We claim:

1. In a dryer of the type which utilizes a rotatable clothes containingcylinder having a.

solid peripheral wall and a perforated front wall,

an air circulating duct adjacent said perforated front wall of saidcylinder, an inlet opening in said duct adjacent said perforated frontwall of said cylinder into said duct, an outlet opening in said ductthrough which the air flows into said cylinder from said duct, a gasburner located adjacent to said duct outlet, a conduit for carrying theheated air and products of combustion from said burner, said conduitpassing through said air duct, a mixing chamber at the outlet of saidconduit, said mixing chamber having one of its sides provided withopenings adjacent the solid peripheral wall of said rotatable cylinderto permit heat transfer through said peripheral wall and subsequentadmission of said mixed air and products of combustion into said clothescontaining cylinder through said perforated front wall.

2. In a dryer of the type which utilizes a rotatable drum having ascreened or perforated front wall to contain the clothing or otherfabrics to be dried, an air circulating duct having an open portionadjacent said screened front wall, a blower positioned in said duct forproducing a flow of air therethrough, a gas burner, and a conduit forcarrying the heated air and products of combustion from said burner,said conduit being positioned adjacent to said screened front wall andinside said duct adjacent said open portion permitting a transfer of theheat radiated from said conduit through said screened front wall andinto said drum and also a, transfer of radiated heat to the air in saidduct.

3. In a dryer of the type which utilizes a rotatable drum having ascreened or perforated front wall to contain the clothing or otherfabrics to be dried, an air circulating duct having an open portionadjacent said screened front wall, a blower positioned in said duct forproducing a flow of air therethrough, a gas burner, a conduit forcarrying the heated air and products of combustion from said burner,said conduit being positioned adjacent to said screened front wall andinside said duct adjacent said open portion permitting a transfer of theheat radiated from said conduit through said screened front wall andinto said drum and also a transfer of radiated heat to the air in saidduct, and a mixing chamber at the outlet of said conduit into whichheated air and products of combustion from said gas burner may bedischarged, said mixing chamber being located adjacent a peripheral wallof said rotatable drum and having perforations or openings thereinthrough which the hot air and products of combustion may escape tocontact said peripheral wall and subsequently to enter said drum throughthe perforations in the front wall thereof.

4. In a dryer of the type which utilizes a rotatable drum having ascreened or perforated front wall to contain the clothing or otherfabrics to be dried, an air circulating duct having an open portionadjacent said screened front wall, a blower positioned in said duct forproducing a flow of air therethrough, a gas burner, a conduit forcarrying the heated air and products of combustion from said burner, aidconduit being positioned adjacent to said creened front wall and insidesaid duct adjacent said open portion permitting a transfer of the heatradiated from said conduit through said screened front wall and intosaid drum and also a transfer of radiated heat to the air in said duct,a mixing chamber at the outlet of said conduit into which heated air andproducts of combustion from said gas burner may-be discharged, saidmixing chamber being located adjacent a peripheral wall of saidrotatable drum and having perforations or openings therein through whichthe hot air and products of combustion may escape to contact saidperipheral wall and subsequently to enter said drum through theperforations in the front wall thereof, and an air inlet to admitoutside air to said mixing chamber to combine with the products ofcombustion contained therein.

5. In a dryer of the type which utilizes a rotatable drum having ascreened or perforated front wall to contain the clothing or otherfabrics to be dried, an air circulating duct, a blower positioned insaid duct for inducing a flow of air therethrough, a gas burner, aconduit for carrying the-heated air and products of combustion from saidburner, said conduit being adjacent said screened front wall and insidesaid duct, 9, housing surrounding said conduitf reventing contact of theair in said duct with the exterior walls of said conduit, said housingbeing open on the side facing said screened front wall of said drumpermitting a transfer of heat radiated from said conduit through saidscreened front wall and into said drum, the walls of said housingpermitting the heat radiated from said walls to heat the air circulatingin said duct, a chamber at the outlet of said conduit into which heatedair and products of combustion from said gas is discharged, and anoutlet from said chamber to permit the escape of said heat and productsof combustion from said chamber around and into said rotatable drum.

6. In a dryer of'the type which utilizes a rotatable clothes containingdrum having a screened or perforated front wall, an air circulatingduct, a blower positioned in said duct for producing a flow of airtherethrough, a gas burner, a conduit for carrying the heated air andproducts of combustion from said burner, said conduit being adjacentsaid screened front wall and inside said duct, a housing surroundingsaid conduit preventing contact of the air in said duct with theexterior walls of said conduit, said housing being open on the sidefacing said screened front wall of said drum permitting a transfer ofheat radiated from said conduit through said screened front wall andinto said drum, and an inlet opening in said housing permitting outsideair to enter into said housing'and flow around said conduit and intosaid rotatable drum through said screened front wall of said drum.

'7. In a dryer of the type which utilizes a rotatable clothes containingcylinder having a screened or perforated front wall, an air circulatingduct, a blower positioned in said duct, an inlet opening in said ductadjacent said blower and said screened front wall through which air iswithdrawn from said cylinder into said duct by the action of saidblower, an outlet opening in said duct through which air is forced outof said duct into said cylinder, a gas burner located adjacent to saidduct outlet, a conduit for carrying the heated air and products ofcombustion from said burner, said conduit being adjacent said screenedfront wall and inside said duct, a housing surrounding said conduitpreventing contact of the air in said duct with the exterior walls ofsaid conduit, and an opening in said housing permitting outside air toenter into said housing and flow around said conduit and into saidrotatable cylinder through said screened front wall thereof at a pointsufficiently close to said duct outlet to permit the air from both saidoutlets to mix as it flows into said rotatable cylinder.

8. In a dryer of the type which utilizes a rotatable clothes containingcylinder having a screened or perforated front wall, an air circulat- 1ing duct, a blower positioned in said duct, an inlet opening in saidduct adjacent said blower and said screened front wall through which airis withdrawn from said cylinder into said duct, an outlet opening insaid duct through which air is forced out of said duct into saidrotatable cylinder, a as burner located adjacent to said duct outlet, aconduit for carrying the heated air and products of combustion from saidburner, said conduit being adjacent said screened front wall and insidesaid duct, a chamber at the outlet of said conduit to receive the heatedair and products of combustion carried by said conduit, said chamberhaving openings communicating with the interior of said rotatablecylinder, a housing 15 surrounding said conduit preventing contact ofthe air in said duct with the exterior walls of said conduit, and aninlet opening in said hous- Permitting outside air to enter into said 12housing and flow around said conduit and into said rotatable cylinderthrough said screened front wall thereof at a point suiiiciently closeto said duct outlet to permit the air from both said 5 outlets to mix asit flows into said rotatable cyl- 10 REFERENCES cr'rnn The followingreferences are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,646,223 Stricker Oct. 18, 19272,389,443 Hough Nov. 20, 1945

